Synthetic drying compositions



Patented Apr. 4,

UNITED STATES PATENT OFFICE 2,502,518 SYNTHETIC name COMPOSITIONS NewYork No Drawing. Application May 21, 1946,

' Serial No. 671,390

. 7 Claims. 1 This invention relates to new synthetic compositions andmore particularly to compositions which are polymeric esters derivedfrom the reaction of polyhydric phenols and polybasic acids which arepolymeric oil acids.

The new compositions are polymeric esters of the polyhydric phenols withthe polymeric drying oil acids, or composite or modified compositionscontaining suchesters.

The invention includes the new compositions and articles and productsmade therefrom.

The new compositions are useful for the production of films, articlesand other final reaction products of outstanding properties.

The invention is based on the discovery that improved compositions canbe produced by esterifylng polyhydric phenols and particularly dihydricphenols with polymeric oil acids and particularly with dimeric acidsderived by the polymerization of unsaturated fatty acids such as thosederived from soy bean oil and linseed oil.

We have found that valuable drying compositions can be prepared by theesteriilcation of polyhydric phenols and dihydric phenols with suchdimeric drying oil acids and that drying compositions can be therebyproduced which are useful in making varnishes, compositions forvulcanlzation, etc.

The new compositions are prepared by esterifying the dihydric phenolswith the dimeric oil acids. We have found that these polyesters can beprepared by an acid interchange reaction between the dimeric oil acidsand the dihydric phenol diacetates without going to excessively hightemperatures which would lead to discoloration and in some cases toexcessive polymerization or bodying. Our method is economical and givesexcellent yields whereas the usuaUmethods-for preparing phenol esterssuch as reactions of acid halides and acid anhydrides with phenols inthe presence of basic reagents, besides being less economical, haveother disadvantages such as yielding impure products and products havinga darker color.

Briefly. our process involves heating the dimeric oil acids with lowboiling monobasic acid diesters of dihydric-phenols, that is diacetatesor dipropionates (we prefer diacetates for economic reasons), attemperatures of about 180 to 275 C., and preferably at 200 to 250 C.while blowing the reaction mixture with an inert gas such as nitrogen orcarbon dioxide to facilitate the removal of the liberated acetic acidwhich is collected in a suitable trap by known methods. The inert gasalso serves to protect the ester from discoloration which usuallyaccompanies exposure of this type of material to air or oxygen at hightemperatures.

The diacetates of dihydric phenols can be prepared in excellent yieldsby known methods using acetic anhydride, acetyl chloride or ketene. Weprefer to use acetic anhydride for economic reasons. The diacetates ofmany dihydric phenols are crystalline compounds. Thus the acetylationstep serves as a convenient method for purifying the dihydric phenol bycrystallization of the diacetate in addition to putting it into a formfor esteriflcation by acid interchange.

In cases where the starting dihydric phenol is sufilciently pure to givelight colored products or where the color of the polyester is of noobject, the diacetate need not be isolated from the acetylation solutioncontaining liberated acetic acid and any excess acetic anhydride whichwas used in its preparation. The dimeric oil acid can be added directlyto the acetylation mixture and the mixture treated in the same manner aspreviously described. The excess acetic anhydride is driven out by theinert gas and is trapped with the liberated acetic acid.

Another method of practicing our process of esterlfication is to heat amixture of the dihydric phenol, dimeric oil acid and acetic anhydride(the acetic anhydride may be in equivalent amount or in excess),removing the liberated acetic acid through a suitable fractionatingcolumn at such a rate which will prevent the escape of acetic anhydride.In this case the acetylation of the dihydric phenol and the acidinterchange reaction with the dimeric oil acid take placesimultaneously. As the reaction nears completion, the temperature of thereaction mixture rises and at a temperature of about 200 to 225 C. aninert gas is bubbled through the mixture to remove all of the liberatedacetic acid and any excess acetic anhydride which may have been used.

Regardless of which of these methods is used, polyester formation takesplace at temperatures from about 180 to 275 C., preferably at 200 to250. Below 180 C. polyester formation becomes very slow and above 275 C.thermal decomposition and discoloration of the reactants and productsmay occur. Where very stable reactants are used and where polymerizationdue to unsaturation of either or both of the reactants do not interfere,temperatures of 250 to 275 C. may be used giving very rapid polyesterformation. However, polyester formation is usually quite rapid at 225 to250 C. and in some cases takes droxyl groups.

place very rapidly 'even at temperatures as low as 190 to 200 C.

Where highly unsaturated dibasic acids such as dimerized soy bean acidsor dimerized linseed acids are used for polyester formation. it isusually best to avoid temperatures in excess of 250 C. and preferably towork at temperatures as low as possible without unduly prolonging thetime of esterification. A rapid stream of inert gas serves to decreasethe time of esteriflcation a great deal. Likewise with substances whichare very sensitive to discoloration, it is best to work at the lowestpossible temperatures, usually at about 200 C. or at times as low asabout 180 C.

Various polyhydric phenols can be used in making the new compositions.In general, the polyhydric phenols used may be any of the usual types ofpolyhydric phenols having two phenolic hydroxyls attached to separatearomatic nuclei so long as they do not contain any chemical groups whichwill interfere with the reaction of the carboxylic acids with thephenolic hydroxyl groups in preparing the new products. The polyhydricphenol may thus contain two or more phenolic hydroxyl groups indiflerent benzene nuclei as is the case in fused ring systems such asnaphthalene or in molecules in which the different benzene nuclei areattached by chains composed of carbon atoms and/or other atoms.

Illustrative of the polyhydric phenols which may be used in producingthe new compositions of the present invention are bisphenol(p,p'-dihydroxydiphenyl dimethyl methane) p,p -dihydroxydiphenylsulfone, dihydroxybenzophenones, dihydroxynaphthalenes,dihydroxydiphenyls, trihydroxynaphthalene, tetrahydroxynaphthalene, etc.

Still another type of polyhydric phenol which may be used in making thenew compositions of the present invention is that derived by thereaction of a polyhydric phenol with polyhalides, using proportions ofthe reactions such that the final product contains unreacted phenolichy- For example, a dihydric phenol may be obtained by the reaction ofsay, three mols of bisphenol with two mols of dichlorodiethylether inthe presence of alkali to give a long chain dihydric phenol. It will beunderstood that such complex dihydric phenols are mixtures and that inconsidering them as dihydric phenols they should be considered as havingan average molecular weight corresponding to the ratio of reactants usedin their preparation.

Compositions of somewhat different properties can be made fromdifl'erent polyhydric phenols. Particularly valuable compositions can bemade by the use of high molecular weight dihydric phenols such asp,p'-dihydroxydiphenyl sulfone.

The polybasic acids used in making the new compositions are derived fromthe polymerization of unsaturated oils or the acids derived therefrom.The general procedure used in the preparation of the so-called dimericacids consists in heating the unsaturated oil or one of its derivativessuch as the free acids or methyl esters to high temperatures with orwithout the aid of a catalyst, in which case polymerization takes placethrough the double bonds to give polycarboxylic acids which are for themost part dibasic acids derived from the union of two unsaturated carbon chains through their double bonds. Dimeric acids may thus be readilyprepared by the polymerization of linseed oil acids or soy bean oilacids and the dimeric acids so produced are for the most part derivedfrom the union of two eight- 4 een-carbon atom chains through theirdouble bonds.

Such polymeric products are commonly referred to as dimeric acids butmay contain small and varying percentages of higher polymeric acids suchas trior tetrameric acids.

Such polymeric products may be freed from unpolymerized acids by solventextraction or vacuum distillation. In some cases unpolymerized dryingoil acids are advantageously present admixed with the polymeric acids,giving somewhat modified products when reacted with the poly hydricphenols to form new synthetic drying esters.

The proportions of dihydric phenol and dimeric acid used in making thenew compositions can be somewhat varied. Since the dihydric phenols anddimeric acids are both difunctional they react to form polymericproducts with the dihydric phenol residue and the dimeric acid residuealternating and being connected through ester linkages. Proportionsapproximating equivalent proportions are advantageously used orproportions containing a small excess of the dihydric phenol.

It is sometimes desirable to use small and varying amounts of monobasicacids and particularly of drying oil acids along with the dimeric acidsin forming the new drying compositions.

The new compositions made from dihydric phenols and dimeric oil acidsare particularly advantageous drying compositions, since they giveproducts which are in general soluble in hydrocarbon solvents,particularly the aromatic type, and such solutions may be used asvarnishes to give valuable protective coatings. Such compositions arecapable of converting on exposure to air or with heat treatment and theyare also capable of being vulcanized with the usual type of vulcanizingagents used in rubber manufac= ture.

Instead of using a single dihydric phenol and a particular dimeric acid,mixtures of polyhydric phenols can be used or mixtures of dimeric acidsor of both, and products of somewhat different and varying propertiescan be obtained depending upon the polyhydric phenol or phenols and thedimeric acids used.

The character of the products can also be varied by varying theproportions of the dihydric phenols and dibasic acids. When equivalentproportions of a dihydric phenol and a dibasic acid are used andcompletely esterifled the theoretical formula would be a linear polymerof inflnite chain length but for practical purposes the reaction iscarried only to the point where a polymeric product is formed which issoluble and useful in making varnish and other compositions.

When preparing drying compositions it is usually desirable to use amolar ratio near to 1:1 with the dihydric phenol diacetate in slight excess. The chain length and hence the viscosity can be regulated bychanging the molar ratio of dibasic acid to dihydric phenol.

When the dimeric acid is in excess, the polyester is itself a dibasicacid and when the di- 'hydric phenol is in excess the polyester is adihydric phenol or its diacetate, depending upon the quantity of aceticanhydride used in preparing the dihydric phenol diacetate. Thus, forexample if 4 mols of dihydric phenol and. 3 mols of dimeric acid are tobe esterified, the use of 8 or more molsof acetic anhydride would yield.,a polyester which would be a diacetate, whilethe use of 8 mols ofacetic anhydride (exactly equivalent to the dimeric acid used) wouldyield a polyester which is a dihydric phenol, that is having freeterminal phenolic hydroxyl groups.

Thus genera] Formula I theoretically repre-' sents the type of productswhich can be obtained when an axcess of dibasic acid is used:

where X stands for a hydrocarbon chain and R stands for the aromaticnuclear structure of a dihydric phenol and n is an integer.

When an excess of dihydric phenol diacetate is used the products aretheoretically represented by general formula II:

O O .H.i salsa]. Ola...

When the quantity of acetic anhydride used is exactly equivalent to thequantity of dibasic acid used (that is 2 mols acetic anhydride per molof dibasic acid) with the dihydric phenol in excess of the dibasic acid,the products are theoretically represented by general Formula III:

III.

When monobasic acids are used to terminate the chains the products aretheoretically represented by Formula IV.

Where A is an organic radical such that the acid ACOOH ,hasa boilingpoint above that of acetic acid, but preferably above 200 C.

When monohydric phenols are used to terminate the chains the productsare theoretically represented by general formula V:

where B is a phenyl group, substituted phenyl,

naphthyl or substituted naphthyl group.

Somewhat modified products can be obtained by using small and limitedamounts of monofunctional reactants such as a monofunctional,

following specific examples, but it will be understood that theinvention is not limited thereto. The following typical procedure wasused in the preparation of the dimeric acids referred to in thefollowing examples:

The methyl esters of soy bean oil acids or linseed oil acids were heatedwith continuous agi tation in the presence of .3% to .4% ofanthraqulnone'at a temperature of 300 C. to 325 C. for a period of 15 to20 hours. A slow stream of carbon dioxide was continually bubbledthrough the reaction mixtures during the heating period. The resultingproduct was freed from monomeric methyl esters by distillation at apressure of 1 to 2 mm. until no more distillate could be obtained whenthe polymeric residue was heated in a vessle which was surrounded by anoil bath heated to a temperature of 250 C.

Example I.A mixture of 156 parts of the diacetate of bisphenol and 265parts of dimeric soy been 011 acids was placed in a vessel provided witha stirrer, a thermometer and a condenser connected for downwarddistillation. This reaction mixture was heated with stirring whilepassing a stream of carbon dioxide through the reaction mixture for fourhours during which time the temperature was gradually raised from 200 C.to 249 C. The reaction product was a viscous mass which had an acidvalue of 2.9.

The product when dissolved in xylene to give a varnish of 50% solids hada viscosity of M bubble viscosimeter). This solution when treated with0.05% cobalt drier gave a film which air dried in 26 hours.

Example II.A mixture of 109 parts of diacetate of 4,4'-dihydroxytetraphenylmethane and 135 parts of dimeric soy bean oil acids wasreacted according to the procedure of Example I, heating for 5 hours at200 to 237 C. to give a product which had an acid value of 8.6 and whenthinned to 50% solids with xylene gave a viscosity of Z. This solutionwhen treated with 0.05% cobalt drier gave excellent air dried and bakedfilms.

Example III.-Likewise, a mixture of parts of a diacetate ofp.p-dihydroxy diphenyl sulphone and 160 parts of dimeric linseed oilacids were heated for 43 minutes from 207 to 252 C. to give a viscouswaxlike product of acid values 7.4 and a viscosity of T at 50% solids inxylene.

This solution of 50% solids when treated with .05% cobalt drier (basedon solids) gives an excellent varnish for either air dry or bakingtreatment. Varnish films prepared from this product air dry within aboutfive hours to give a hard, tough, flexible product.

Example IV.A mixture of parts of p,p'-dihydroxydiphenyl sulfone, 265Parts of dimeric soy bean oil acids and 104 parts of acetic anhydridewas heated slowly over a period of about two hours to a temperature of239 C., removing the liberated acetic acid through an eflicientfractionating column. The mixture was continuously agitated during thisheating period. The temperature was held at 239 C. for another 50minutes while bubbling carbon dioxide through the mixture.

The product had an acid value of 2.5 and a viscosity of S in 50% solidsin xylene. This solution when treated with 0.05% cobalt drier formed afilm which air dried in 5 hours.

Example V.A mixture of 100 parts of the diacetate of o-p'-dihydroxydiphenyl sulphone and 160 parts of dimeric soy bean oil acids whenheated for 52 minutes from 229 to 244 C. gave a product having an acidvalue of 9 and a viscosity of B at 40% solids in xylene.

Varnish films prepared from this product containing cobalt drier gavetack free films in about 2 to 3 hours and extremely hard, flexible filmswhen dried for 27 hours. Similar results were obtained when the filmswere baked for 30 minutes at C.

Example VI.A reaction mixture of 96 parts of diacetate of2,2-dihydroxy-1,1'-dinaphthy1 7. methane (methylene, bis-beta naphthol)and 136 parts of dimeric soy been 011 acids was heated for hours at 200to 226 C. to give a viscous product having an acid value of 11.3 and aviscosity of L at 40% solids in xylene.

This product treated with cobalt driver gave varnish films which airdried within one hour to give a tack-free product and the product washard and flexible after two hours drying. Likewise, the product gives anextremely hard, flexible product when baked.

Example VII.-A mixture of 118 parts of a diacetate of2,2-dihydroxy-5,5'-dichlorodiphenyl methane and 177 parts of -a dimericacid obtained by the polymerization of linseed oil acid methyl esterswas heated for 32 minutes at 211 to 228 C. to give a product having anacid value of 5.8 and aviscosity of Y at 50% solids in xylene.

This 50% solution when treated with driers and spread in thin films of.003" thickness air dried in about two hours to give a tack free film;and extremely hard, tough films were obtained on baking for minutes at100 C.

Example VIII.A mixture of 120 parts of a diacetate of221-dihydroxy-1,1'-dinaphthyl and 170 parts of dimeric soy bean oilacids was heated for 4 /2 hours at 221 to 237 C. to give a product ofacid value 2.5 and a viscosity of F at 50% solids in xylene. v

Likewise, this composition gave hard, tough films when air dried for afew hours or when baked at elevated temperatures.

It is characteristic of protective coating films prepared from productsof the type illustrated in the preceding examples that hard, flexibleproducts can be obtained. The flexib lity is probably to be accountedfor in part by the fact that the products are essentially linearpolymers of relatively. long chain length and in part by the fact thatthe percentage of aliphatic structure present aslong chains derived fromthe dimeric acids is relatively high, although the residues of thedihydric phenols in the polymer structure appears to aid in impartingdesirable properties to the new compositions. A product containing about70% of its structure as dimeric acid residues has about the samehardness as would be expected from normal oleoresinous varnishes andalkyds which contain as low as oil modification. This unusual hardnessis apparently due to the fact that high melting rigid structures areintroduced into the polymeric chains by the use of such high meltingdihydric phenol residues.

In the abovefexamples the dihydric phenols and dimeric oil acids areused without admixture of other reactants. It is sometimes des rable touse mixtures of polyfunctional reactants. Phenolic acids having onephenolic hydroxyl and one carboxyl group are such reactants which may beused in admixture with the dihydric phenols and dimeric oil acids.Examples of such phenolic acids are sali-cyclic acid, p-hydroxvbenzoicacid, anac'ardic acid (derived from cashew nut'shells),3-hydroxy-2-naphthoic acid, 4-hydroxyphenyl acetic acid,l-hydroxyphenoxyacetic acid,

and phenolic acids such as obtained by the Friedel-Crafts condensationof 1 mole of phenol with 1 mole of unsaturated acids such as oleic,linoleic, linolenic, etc. or with one mole of a halogenated acid such as2-chlor0stearic acid, beta-chloropropionic acid, lz-bromostearic acid,

etc. The following example illustrates the use of such mixtures, theacetate of salicyclic acid acting as a difunctional reactant, having acarboxylic acid group which can esterliy the dihydric phenols and havinga phenolic hydroxylic group which can in turn be esterified by thedimeric acids. 1

Example IX.-A mixture of parts of the diacetate ofp,p'-dihydroxydiphenyl sulfone, parts of dimeric soy bean oil acids and68 parts of the acetate of salicyclic acid was heated for 6 hours and 45minutes at 200 to 229 C. to give a product of acid value of 4.8 and aviscosity of I at 50% solids in xylene.

This composition when treated with driers gave thin films which airdried in about two hours to give hard, tough products.

It is also sometimes desirableto introduce into the new compositionresin acids to give composite rosin modified products, The production ofsuch products is illustrated by the following examples:

Example X.A mixture of 104 parts of the diacetate of bisphenol, parts ofdimeric soy bean acids and 31 parts of rosin were heated for 7 hours at205 to 225 C. to give a product of acid value of 4.8 and a viscosity ofI in 50% solids in xylene.

This product when treated with driers gave .003" films which air driedin about 2 hours to give tack free films.

Example XI.--A mixture of 111 parts of the diacetate of p,p'-dihydroxydiphenyl sulfone, 150 parts of dimeric soy bean oil acid and 38 parts ofrosin was heated for six hours at 200 to 233 C. to give a product ofacid value 10.4 and a viscosity of G at 50% solids in xylene.

This product when treated with drier gave thin films which air dried inabout two hours to give hard infusible products.

It is also sometimes desirable to use monofunctional unsaturated oilacids to produce modification of the products obtained by the reactionof polyhydric phenols with dimeric unsatu-- rated oil acids. Theproduction of such drying compositions is illustrated by the followingexamples:

Example XII.-A mixture of 118 parts of the diacetate of2,2-dihydroxy-5,5'-dichlorodipheny1 methane, 160 parts of dimericlinseed oil acids and 20 parts of unpolymerized linseed oil acids washeated for one and one-half hours at 204 to 233 C. to give a product ofacid value 2.9 and a viscosity of V at 30% solids in xylene.

This product when treated with driers and spread in thin films air driedin about two hours to give hard, infusible products.

Erampe XIII.A mixture of 111 parts of the diacetate ofp,p'-dihydroxydiphenyl sulfone, 150 parts of dimeric soy bean oil acidsand 30 parts of China-wood oil acids was heated together for 2 hours and45 minutes at 200 to 228 C. to give a product having an acid value of10.2 and a viscosity of N at 50% solids in xylene.

This product when treated with driers and spread in thin films gavehard, tough products an acid value of 7.8 and a viscosity of D at 50%solids in xylene.

Similarly this product when treated with driers and spread in thin filmsgave hard, tough prod ucts when air dried overnight or when baked forone-half hour at 150 C.

The foregoing examples illustrate the use of difierent dihydric phenolsand different dimeric acids. It will be understood that other dihydricphenols can be similarly used as well as other dimeric acids of dryingoils and semi-drying oils; and that modified or composite products canbe made from mixtures of the reactants either without or with theaddition of other reactants, such as those above referred to. It willthus be seen that the present invention provides new syntheticcompositions which are polymeric esters of polyhydric phenols andparticularly of dihydric phenols, with polymeric oil acids andparticularly dimeric oil acids, and which are valuable compositions foruse in making films, varnishes, etc., as well as for use in makingvulcanized compositions, etc.

We claim:

1. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimericunsaturated drying oil acids with dihydric phenols having the twophenolic hydroxyls attached to separate aromatic nuclei andsaidpolymeric esters having alternating dimeric acid residues and dihydricphenol residues connected through ester linkages.

2. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimeric soyaoil acids with dihydric phenols having the two phenolic hydroxylsattached to separate aromatic nuclei and said polymeric esters havingalternating dimeric acid residues and dihydric phenol 4 residuesconnected through ester linkages.

3. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimericChina-wood oil acids with dihydric phenols having the two phenolichydroxyls attached to separate aromatic nuclei and said polymeric estershaving alternating dimeric acid residues and di- 10 hydric phenolresidues connected through ester linkages.

4. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimericlinseed oil acids with dihydric phenols having the two phenolichydroxyls attached to separate aromatic nuclei and said polymeric estershaving alternating dimericacid residues and dihydric phenol residuesconnected through ester linkages.

5. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimeric unsaturated drying oil acids with 2,2'-dihydroxy dinaphthyl methane and saidpolymeric esters having alternating dimeric acid residues and dihydricphenol residues connected through ester linkages.

6. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimericunsaturated. drying oil acids with p,p'-dihydroxy diphenyl sulfone andsaid polymeric esters having alternating dimeric acid residues anddihydric phenol residues connected through ester linkages.

7. New synthetic drying compositions capable of forming drying films,said drying compositions being linear polymeric esters of dimeric soyaoil acids with p,p'-dihydroxy diphenyl sulione and said polymeric estershaving, alternating dimeric acid residues and dihydric phenol residuesconnected through ester linkages.

SYLVAN. OWEN GREENLEE. JOHN DAVID ZECH.

nmancas 'crran UNITED STATES PATENTS Number Name Date 2,082,790 Cherry-1--- June 8, 1937 2,239,533 Mikeska Apr. 22, 1941 2,298,914 Auer Oct.13, 1942 2,341,239 Percy et a1. m). 8, 1944 2,373,015 Cowan et al. Apr.3, 1945

1. NEW SYNTHETIC DRYING COMPOSITIONS CAPABLE OF FORMING DRYING FILMS,SAID DRYING COMPOSITIONS BEING LINEAR POLYMERIC ESTERS OF DIMERICUNSATURATED DRYING OIL ACIDS WITH DIHYDRIC PHENOLS HAVING THE TWOPHENOLIC HYDROXYLS ATTACHED TO SEPARATE AROMATIC NUCLEI AND SAIDPOLYMERIC ESTERS HAVING ALTERNATING DIMERIC ACID RESIDUES AND DIHYDRICPHENOL RESIDUES CONNECTED THROUGH ESTER LINKAGES.